Portland International Airport: The visionary main terminal at PDX has a mass timber roof, celebrating Oregon’s forests.

ZGF Architects’ design for the new main terminal at PDX is a finalist in the 8th annual GRAY Awards.

FINALIST

Breakout category: Visionary

Designer: ZGF Architects

Project location: Portland, Oregon, United States

Date of completion: August 202024

Photography: Dror Baldinger, Ema Peter

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SUBMISSION

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Designed to evoke the feeling one gets while walking in the forest, the new main terminal at Portland International Airport (PDX) transcends functionality and creates a sense of wonder inherent to the natural beauty of the Pacific Northwest. The undulating 9-acre mass timber roof celebrates the history and the future of Oregon’s forest product innovation with wood that was sustainably and locally sourced from landowners and mills within a 300-mile radius of the airport. Views of the airfield and the surrounding forested landscape—paired with interior finishes that reference the region’s natural beauty, make it clear upon arrival exactly where you have landed.

The design team looked at urban planning strategies and the terminal houses smaller-scale architecture designed as a “series of rooms” that recreate Portland’s unique, walkable sense of scale and take cues from the city’s short city blocks, parks, and pedestrian-friendly streets. Trees and planters reinforce a neighborhood-like feel and a central boulevard with cafe seating and furniture invite travelers to linger.

The interior environment is designed to increase passengers’ comfort and reduce the stress that many people experience while traveling. PDX has always placed an emphasis on cultivating a sense of place by incorporating elements of wood, plants, and natural daylight into its design. By applying the concept of biophilia holistically throughout the terminal, almost every corner features access to natural light and touches of greenery. Landscaping provides a sense of wandering through a forest and acts as a wayfinding tool guiding passengers from security to their gates.

In addition to the reconfigured and expanded ticket hall, a central threshold directly after ticketing provides a forest-like experience with trees and dappled light that transitions passengers to the TSA security checkpoints and onto their gates. A pre-security marketplace features stadium seating and 30% of the total concessions offering regional goods and dining. The additional 70% of the concessions are located beyond security. Retail concessions were designed as a “kit of parts” with plug-and-play utilities for ease of installation and flexibility in configuration and brand expression.

PDX is the first major airport in the U.S. with a mass timber roof. Mass timber was selected for various reasons including cost, constructability, sustainability—and to celebrate Oregon’s thriving timber industry. The daylighting strategy features 49 skylights that filter daylight through the mass timber roof’s lattice—illuminating 60% of the terminal alongside custom hanging light fixtures. The 9-acre roof is constructed from 3.5 million board feet of wood and three different wood products: mass plywood panels for the roof diaphragm, glulam beams, and 3 x 6-foot timbers for the lattice, eliminating the need for steel hardware. The design conceals a myriad of systems and features 34 massive Y-shaped columns that hold the 18-million-lb, 400,000-sq-ft roof in place. The terminal is designed to withstand a magnitude 9 seismic event.

The wood sourcing strategy supported local economies and promoted forestry practices that protect Oregon’s natural resources. Nearly all of the 2.6M board feet for the glulam and lattice was sourced from forests managed to support strong ecological outcomes. Just like “farm to table” cuisine, over 1 million of the 2.6 million board feet for the glulam and lattice can be traced back to the forest of origin through the direct sourcing approaches.

One of the biggest challenges was how to modernize, renovate, and expand the main terminal while keeping the airport fully operational throughout construction. Instead of building an entirely new terminal, much of the existing infrastructure was reused, enabling the airport to grow in place and increase its capacity to accommodate 35 million annual passengers by 2045. The decision to reuse much of the existing terminal, along with using wood and optimizing steel and concrete, enabled a 70% reduction in the embodied carbon of the structure compared to building an entirely new terminal.

Another key solution was to prefabricate the modular roof structure nearby and then set it over the existing terminal. This allowed construction to take place without disrupting airport operations—reducing the construction timeline and logistical costs. As passenger loads continue to increase, a flexible infrastructure allows for future innovations, evolutions in sustainable design, and the need for future expansions.

DESIGN TEAM:

ZGF Architects

COLLABORATORS:

General contractor: Hoffman Skanska Joint Venture

Pre-construction Services: Turner Construction

Engineers

• Structural: KPFF Consulting Engineers (primary), Arup

• Mechanical/Electrical/Plumbing: PAE Engineers (primary), Arup

• Geotechnical Engineers: GRI

• Civil Engineer and Airside Planning: HNTB

Consultants

• Mass Timber Trade Partner: Swinerton Mass Timber

• Steel Trade Partner: W&W AFCO Steel

• Mass Timber Fabricators/Manufacturers: Zip-O-Laminators, Timberlab, Freres, Calvert

• Mass Timber Manufacturers: Calvert, Freres, Zip-O-Laminators

• Wood Advisor: Sustainable Northwest and Sustainable Northwest Wood

• Lumber Mills: Elk Creek Forest Products, Frank Lumber Co., Freres Lumber Co., Herbert Lumber Co., Kasters Kustom Cuts, Manke Lumber, Zip-O-Log Mills

• Aviation Planning: ARUP USA

• Landscape: PLACE Landscape Architecture

• Biophilic Design Consultant: Terrapin Bright Green

• Sustainability Consultant: ZGF (lead consultant), Arup

• Building Envelope: Professional Roof Consultants Inc., RDH Building Sciences Inc.

• Air & Wind Analysis: RWDI Consulting Engineers & Scientists

• Erector: Derr & Gruenwald Construction

• Heavy Lift/Transport: Mammoet

• Glulam Connections: Madlyn Metals Fab

• Y Column Fabrication: Thompson Metal Fab

• Curtainwall: Benson

• Roofers: Snyder Roofing of Oregon LLC

• Lighting Design: Fisher Marantz Stone

• Signage Consultant: Mayer/Reed Inc.

• Fire Protection: Cosco Fire Protection Inc.

• Electrical: Oregon Electric Group

• Plumbing: Harder Mechanical Contractors

• Acoustics and Public Address: Arup

• Cost Estimating: RLB

• HVAC: Arctic Sheet Metal

• Architectural Metals: McKinstry Co., LLC

• Expansion Joints: Performance Contracting Inc.

Exterior Cladding

• Metal panels: Morin Corp.

• EIFS, ACM, or other: Custom Metal Cladding Ltd.

• Moisture barrier: Henry Co.

• Curtain wall: Benson Curtainwall, Arcadia

• Other cladding unique to this project: Expansion joints by MM Systems, Sunshades by McKinstry

Roofing

• Built-up roofing: Siplast

• Other: Seismic Isolators by Maurer SE

Glazing

• Glass: Carey Glass with Glas Trösch, Viracon

• Skylights: Deamor

Interior Finishes

• Acoustical ceilings: Armstrong World Industries, Inc.

• Wood Flooring: Zena Forest Products

• Paints and stains: Timber Pro

• Special interior finishes unique to this project: Interior sunshades by Levolux

Lighting

• Interior ambient lighting: Acuity Custom Architectural Lighting

• Downlights: Acuity Custom Architectural Lighting, Flos, Meteor

• Exterior: Musco

Lighting

• Dimming system or other lighting controls: ETC Inc.

Forests of Origin/Wood Harvest Sites:

Camp Adams Youth Camp, Camp Bishop Gray’s Harbor YMCA, Camp Namanu, Chimacum County Park, The Nature Conservatory Central Cascades Forest, Coquille Indian Tribe, Hanschu Family Forest, Hyla Woods, Joint Base Lewis McCord, Roslyn City Forest, Skokomish Indian Tribe, Willamette University Educational Forests, Yakama Nation

DESIGNER PROFILE:

ZGF Architects LLP is a design firm with a focus on architecture, interior design, and urban design. Founded in Portland, Oregon, our mission is to strive for design excellence, stewardship of our natural and built environment, a commitment to social equity and diversity in the profession, and exceptional client service. The firm has grown to include offices in Seattle, Los Angeles, Washington, DC, New York, Denver, and Vancouver, BC. Attention to craft and beauty is elemental to the ZGF culture. Our deep respect for the built environment evolved from reverence for the surrounding natural beauty of the Pacific Northwest landscape and a commitment to stewardship of the natural environment. Rather than reflecting a signature style, our work is derived from the particulars of climate, context, and the human experience. ZGF's design philosophy is centered on the premise that design excellence should be reflected in every aspect of a building—its fit with the community, its function and relationship to its users, its building systems, and its cost. Our diverse design portfolio allows us to make a difference at all scales and for all people with services ranging from transportation terminals, commercial office and mixed-use developments to corporate campuses, healthcare and research buildings, academic facilities, libraries, and museums.

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The 8th Annual GRAY Awards is sponsored by: